It is taking a little bit longer than expected to get a personal helicopter off the ground.

AirScooter, which hopes to sell a line of mini-helicopters, has tweaked the design of its maiden vehicle and will try to move it into production in 2007, said Dwaine Barnes, the company's president. The company is also in the process of getting the approval to sell the machines. When the production and regulatory issues are clearer, the company will figure out its sales road map.

Earlier, AirScooter was aiming to get a copter out in late 2005 or 2006. The delay largely stems from production delays and extra testing associated with the vehicle's AeroTwin engine.

The AirScooter II can hover or fly at 55 knots. It weighs about 300 pounds and will sell for around $50,000.

The sky is the new frontier for a small group of entrepreneurs. Terrafugia, a start-up out of the Massachusetts Institute of Technology, plans to come out with a "roadable plane"--it drives like a car, but then the wings fold down to turn it into a plane. Terrafugia envisions its flying cars as transportation vehicles that will let commuters make 100- to 500-mile hops rather than drive.

By contrast, AirScooter is in it for fun. Its copters are for recreational use. The company was founded by Elwood "Woody" Norris, a prolific solo inventor.

Some things have changed on the original design. For one thing, the company is now using a stronger composite rotor blade than on earlier models, said Barnes.

The company also swapped out the two-stroke motor that had been used originally for a more powerful, four-stroke version, Barnes noted.

"Two-stroke motors just aren't made for helicopters," he said.

Correction: This story gave an incorrect last name for AirScooter's founder. The company was founded by Elwood "Woody" Norris.